I'm in the process of building an indoor box turtle enclosure for a three toed and eastern box turtle. I would like to make sure that everything is done correctly so that my box turtles are safe since they will be indoors at least 8 or 9 months of the year. I have painted the wood for the enclosure and am now putting many coats of spar urethane over top of the paint to make sure that everything is water resistant and can be cleaned easily. I've noticed that other people have used an eco friendly/non toxic stain on their enclosure's and was wondering if the spar urethane will be toxic in any way to them, and if so where might I buy this non toxic gloss?